Endotracheal intubation is used to provide mechanical ventilation to patients who are unable to breath on their own. A tube is inserted into the trachea through the mouth to maintain an open airway, while a ventilator moves breathable gases in and out of the lungs. Mechanical ventilation requires keeping pressure in the lungs from the ventilator. An inflatable cuff connected to the endotracheal tube and positioned inside the trachea, seals the lungs and allows ventilation. The inflatable cuff also prevents oral secretions from reaching the lungs, when the glottis is kept open due to intubation. The inflatable cuff should provide the proper amount of pressure against the tracheal wall in order to effectively seal the lungs. If the pressure exerted by the inflated cuff is too high, the cuff may cause damage to the trachea. Insufficient pressure may result in insufficient sealing of the trachea, thus allowing aspiration of oral and gastric secretions into the lungs, with may result in ventilator-associated pneumonia. In practice, however, pressure sufficient to prevent all fluids from entering the lungs will cause damage to the trachea.
Oral secretions are produced by salivary glands, whose ducts open into the oral cavity. Salivary glands may produce approximately one liter of oral secretions per day. If oral secretions, potentially containing infectious bacteria, enter the lungs patients are exposed to the risk of contracting life-threatening infections, such as ventilator-associated pneumonia. Removal of oral secretions from intubated patients would reduce the risk of contracting ventilator-associated pneumonia.
Endotracheal tubes having lumen suction tubes for suctioning oral secretions are known. For example, International Application, International Publication Number WO 92/007602, describes an endotracheal tube, which provides gentle suction action to the tracheal wall. The endotracheal tube includes a main lumen, and an inflatable cuff connected to a cuff lumen for inflating and deflating the inflatable cuff. The endotracheal tube also includes a double lumen, which extends parallel inside the wall of the endotracheal tube and ends proximal to a suction eye, located proximal to the inflatable cuff. The double lumen includes a first lumen, and a second lumen, separated by a separation wall. In order to exercise gentle suction, the separating wall terminates approximately 5 mm from the beginning of the suction eye. However, if the cuff does not make a good seal, or when the cuff is deflated to remove the device from the patient's trachea, oral secretions present in the trachea may reach the lungs. Similar devices are described in German Patent No. DE 69126797, and International Applications, International Publication Numbers WO 95/23624, WO 99/38548, and WO 2010/067225.